a) Field of the Invention
This invention relates to conveyor systems for moving load carrying units, such as carts or pallets along a path defined by a conveyor system. More particularly, the invention relates to a load carrying unit including a vertically movable pin for engagement with an endless chain of a conveyor system. Even more particularly, the invention is directed to a stabilizing means for stabilizing vertically movable engaging pins of a load carrying unit when the pin is in a disengaged position.
b) Description of the Prior Art
Conveying systems for moving work pieces from work station to work station including conveyors which generally move at a constant speed and include load carrying units which can be coupled for movement therewith between work stations and uncoupled from the conveyor so that they will be stationary at the work stations while work is done on a work piece carried by the load carrying units are well known. Examples for these conveying systems are set forth in a number of U.S. patents including U.S. Pat. Nos. 4,438,702; 4,644,869; 4,638,740; 4,770,285; and, 5,065,678.
In these conveyor systems, the load carrying units are provided with vertically movable pins for engaging and disengaging with movable endless chains which move at a constant and continuous speed. Many different means have been used for moving these vertical pins from an engaging to a disengaging position and problems have been encountered in maintaining these pins in a disengaged position as the endless chain continues to move beneath the pins. U.S. Pat. No. 4,944,228 teaches one means for stabilizing the engaging pins in a disengaged position.